The present invention relates to a portable lamp and more particularly to a portable reading lamp which can be supported on a conveniently available surface, for example a user's body, so that the light can be directed upon an object such as a book, for example, while the lamp remains in a stable position.
Portable lamps to be attached to a user have been proposed. For example, U.S. Pat. No. 1,319,997 discloses a commonplace flashlight arranged for attachment to apparel, such as a cap, to assist in repair of vehicles. Portable reading lamps are known which can be attached to furniture (U.S. Pat. No. DES. 293,029), reading material (U.S. Pat. No. 4,432,042), or to a lap-positioned portable desk (U.S. Pat. No. 4,700,634). One problem that exists in connection with the use of such portable reading lamps is that they are poor solutions to the need for exclusively illuminating reading material without diminishing the comfort of the user, or disturbing other occupants of the darkened space. An example of such circumstances is use of a portable reading lamp while the user is in bed or resting on a chair. Another problem is that portable reading lights frequently utilize pivoted extensions which can present a hazard to the user should he/she fall asleep. Such extensions also suffer from the disadvantage that they can catch on delicate fabrics. Further extensions increase the cost of manufacture of the reading lamp.
A portable reading lamp for illuminating only the reading material should be simple and economical to manufacture and avoid extensions that can catch on material or poke out an eye. Such lamps should be capable of being directed toward the material being read, while at the same time, not being in the line-of-sight of any occupant of the space, or inadvertently being re-directed in that direction. For convenience, the lamp should be within easy reach of the user and be relatively close to the reading material. The lamp should be easily adjustable or positionable, while at the same time, the pattern of illumination should be insensitive to minor movements and capable of easy direction.
U.S. Design Pat. No. DES. 358,984, proposes a lighted bookmark wherein a miniature arrangement develops a relatively low-power illumination and uses a small battery. Other techniques relying on the reading material for support have also been used. For example, the aforenoted U.S. Pat. No. 4,432,042, directed to a book-light supported by the pages or cover of a book, offers a lamp attached to an adjustable linkage that is clamped to the book, the lamp being powered by a small battery or a transformer-rectifier connected to household electricity. In these proposed designs, the light will move with the reading material, and consequently, such movement may disturb adjacent occupants of the space. In addition, the added weight of the lamp apparatus is cantilevered to some extent outwardly from the book, depending on design and individual adjustment, thereby causing fatigue to the user, when holding book and lamp in position. It is not uncommon for people to fall asleep while reading. Thus, the tubular post or connecting arm could present a danger should the person fall into it.
U.S. Pat. No. 4,700,643 discloses a reading lamp mounted to a lap-positioned desk. The lamp is attached to an articulatable arm, which is attached to a rigid work surface having a cushioned portion underneath. The cushioned portion provides comfort by separating the work surface from the body of the user, and by presenting a resilient surface in contact with the user's body. The cushioned portion has a fixed profile, for example, a tapered profile which provides a slanted work surface and the articulatable arm extends upward in front of the user.
Each of these approaches offer varying degrees of personal illumination to the user. Major factors effecting the ability to provide maximum personal illumination while minimizing disturbance to other individuals include the design of the reflector, lens, lamp, the stability and adjustability of the lamp-mounting arrangement, and the stability of the object on which the lamp is mounted or attached. These factors also determine the useful distance between lamp and illuminated object, but, as with many articles of manufacture, the more sophisticated the design, the greater the cost of manufacture.
The problem to be solved is to provide, at a commercially viable cost and design, a reading lamp which is easily mounted on most surfaces, including the user's body, relatively safe to use, and adjustable in such a way that the light beam is acceptably stable and has a sufficiently narrow span of illumination to achieve an acceptable level of illumination, while being restricted to the reading material.